diff -r cf91a3a20d0d -r 7b134c27fadb main/task_sdcard.c
--- a/main/task_sdcard.c	Sun May 19 21:05:07 2019 +0200
+++ b/main/task_sdcard.c	Mon Jul 01 23:15:49 2019 +0200
@@ -16,7 +16,8 @@
 #include "driver/sdmmc_host.h"
 #include "driver/sdspi_host.h"
 #include "sdmmc_cmd.h"
-#include "diskio.h"
+#include "diskio_impl.h"
+#include "diskio_sdmmc.h"
 
 #include "config.h"
 
@@ -91,7 +92,7 @@
 
 void log_json(void)
 {
-    char        filename[32], strftime_buf[64];
+    char        filename[64], strftime_buf[64];
     FILE	*f;
     bool	addcomma = true;
 
@@ -139,7 +140,7 @@
 
 void log_annotation(int annotation_type, char *label)
 {
-    char        filename[32];
+    char        filename[64];
     char	bordercolor[9], color[9], pos[8];
     FILE        *f;
     bool        addcomma = true;
@@ -174,7 +175,7 @@
 	    fclose(f);
 	}
 
-	snprintf(json_log->time, 8, "%02d:%02d", Hour, Minute);
+	snprintf(json_log->time, 11, "%02d:%02d", Hour, Minute);
 	f = fopen(filename, "a");
 	if (f) {
 	    if (addcomma) {
@@ -465,7 +466,8 @@
 	    if (dir != NULL) {
 		struct dirent   *de = readdir(dir);
 	    	while (de) {
-		    sprintf(lf, "/spiffs/log/%s", de->d_name);
+		    sprintf(lf, "/spiffs/log/");
+		    strncat(lf, de->d_name, 31 - strlen(lf));
 		    if (unlink(lf) == ESP_OK) {
 		    	ESP_LOGI(TAG, "Removed old %s", lf);
 		    }